Tertiary alkali intrusive rocks (WATas;0)

State	Washington
Name	Tertiary alkali intrusive rocks
Geologic age	Probably Eocene
Original map label	Tas
Comments	Syenite sills in Stevens County more precisely defined as leucocratic shonkinite (Yates and Engels, 1968); porphyritic syenite of Danville area (often referred to as Alkalic rocks of Shasket Creek) more precisely defined as hornblende syenite, pyroxene or nephaline syenite, shonkinite, and monzonite (Stoffel, 1990, Parker and Calkins, 1964). Small polygon in northern Ferry County tagged as WAEv1b in digital coverage is really WATas in original map.
Primary rock type	syenite
Secondary rock type
Other rock types
Lithologic constituents	Major Igneous > Plutonic > Syenitic > Syenite (Dike or sill)
Map references	Huntting, M. T., Bennett, W. A. G., Livingston, V. E. Jr., Moen, W. S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.
Unit references	Huntting, M. T., Bennett, W. A. G., Livingston, V. E. Jr., Moen, W. S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000. Parker, R. L. and Calkins, J. A., 1964, Geology of the Curlew Quadrangle Ferry County Washington, U.S. Geological Survey Bulletin 1169, 95 p. [http://pubs.er.usgs.gov/publication/b1169] Yates, R. G. and Engels, J. C., 1968, Potassium-Argon Ages of Some Igneous Rocks in Northern Stevens County, Washingon: U. S. Geological Survey Professional Paper 600-D, p. D242-D247. [http://pubs.er.usgs.gov/publication/pp600D] Stoffel, K. L., 1990, Geologic Map of the Republic 1:100,000 Quadrangle, Washington: Washington Division of Geology and Earth Resources Open File Report 90-10, 62 p, 1 pl.
Geographic coverage	Ferry - Stevens